Laser treatment has been employed for many years in treating conditions of the eye. For example, application of a laser to a target zone defined on selected tissue can be used to generate an elevated level of energy within the target zone, sufficient to coagulate the tissue. In one common application, photocoagulation of the retina is the standard of care for several retinopathies. In photocoagulation, it is important to deliver the correct dose of energy to the treated locations. Doses that are too small will have little or no therapeutic effect, while doses that are too large can rupture or otherwise damage the retina.